In the early 1970s can ends were placed manually into bags, and the bags were loaded manually into pallet for use at filing/closing machinery. In the mid-1970s semi-automatic bagging equipment was introduced in an effort to keep up with the increased output of newer conversion presses, and that development led to automatic bagging machines, which were first introduced in the mid-1980s. Some of the impetus for this development was the monotony of repeated manual operations, which also appeared to be the cause of repeated strain to the hands of those doing the bagging.
Those automatic machines formed a “stick” of ends and then packaged them 1) by wrapping them from a coil or reel of paper or plastic, or 2) placing the sticks into preformed bags. It was found that kraft paper was the preferred wrapping material since it can be recycled, and since it will “breathe” to void fumes which may linger with the stick of ends from synthetic sealing compounds applied to the ends in an earlier operation, or to void moisture which may linger from water based compounds.
In the early patent prior art, the disclosures in U.S. Pat. Nos. 3,337,064, 3,417,853, 3,545,631 and 3,618,530 are representative of systems which use a pneumatic or similar input conveying system for the individual can ends, and troughs or the like for gathering the ends in a face to face on-edge stack. Mechanical feeding mechanisms engage the curl edges of the generally vertically positioned ends and move them into the input or receiving end of a stack forming in a trough, then the ends are supplied to a filling and closing (end curling) machine. Wrapping a stack is not disclosed, and the filled trough is intended to function as a reservoir for smooth steady supply of ends to the closing machine.
In U.S. Pat. Nos. 3,722,741, 4,000,709, 4,537,550, 4,676,708 and 5,335,810 more sophisticated buffer systems for stacks of ends are disclosed, wherein the stacks are separated according to a count of stacked ends, and those stacks are loaded into successive vertically arranged carriers on an endless, carrousel-type conveyor which supplies the stacks to a closing machine.
U.S. Pat. No. 3,878,945, and its various divisions U.S. Pat. Nos. 3,962,845, 3,971,189, 4,051,965, and 5,119,617, all disclose features of an automatic bagging system in which ends are supplied to a gathering and counting deice which separates ends into stacks (or “sticks”), wrapping devices for loading the stacks into individual bags, and mechanism for loading the wrapped stacks onto pallets.
U.S. Pat. No. 4,364 relates to a conveying improvement for gathering ends, providing temporary spacing thereof to facilitate curing of previously applied end seam compound. U.S. Pat. No. 4,655,350 discloses an improvement for detecting and removing ends which have been reversed face-to-back (e.g. public to product sides) in the formation of a stack. U.S. Pat. No. 4,742,669 discloses and improved end counting device in the end counting and stack forming systems. U.S. Pat. No. 5,005,340 discloses a system for inspecting an assembled stack of ends. U.S. Pat. No. 5,372,245 discloses an improved drive for an in-feeding array of assembled ends. U.S. Pat. No. 5,524,947 discloses an improved mechanism for picking and placing stacks (also called “sticks”) of ends in the bagging and palletizing process.
U.S. Pat. Nos. 4,537,010 and 5,372,473 disclose more advanced devices for handling bagged stacks of ends and placing them into pallets.
Thus, prior art automatic bagging machines allow lanes of ends from the output of a conversion press to be counted, separated in stacks or sticks, the stacks placed into individual bags, and the bagged stacks are then loaded into a common palletizer, from which a supply is provided to one or more filling and closing devices.